1. Field of the Invention
The present invention relates to air pressure valves and gauges and more particularly to a tire valve having a pressure gauge combined therewithin, and to a pencil type pressure gauge with a rotary dial.
2. Brief Description of the Prior Art
Standard tire valve stems are designed simply to house a valve to regulate the flow of air into and out of tires. In order to measure the pneumatic pressure within a tire, a separate tire gauge must be used, and this involves much time and inconvenience. Without properly inflated tires, a motor vehicle's handling and braking ability is greatly reduced, while the rate of gasoline consumption and tire wear is increased.
A tire valve stem with a built-in pressure indicator eliminates the need to carry a separate tire gauge to measure the pneumatic pressure of a tire. Reading the air pressure of a tire can be accomplished at a glance. There is no need to unfasten a valve cap, or to insert a tire gauge into the nozzle. The present design configuration is arranged in a manner which will allow for the constant monitoring of pneumatic tire pressure. It is intended to aid in the promotion of traffic and air safety while reducing the rate of unnecessary gasoline consumption and tire wear.
Present pencil type tire pressure gauges are comprised of an indicating bar with a measurement scale, a spring and a piston housed in a tube. Without a properly sealed piston, the pressure reading of the gauge will be inaccurate. Additionally, a new reading must be taken whenever the gauge is removed from the tire valve stem.
A pencil type tire gauge with a rotary dial indicator having numerals disposed can provide an easy to read pressure display. Additionally, using a sealed bellows provides an accurate pressure reading. Finally, the push button type control valve with the valve core engaged at the lower end of the gauge allows the pressure reading to remain on the rotary dial indicator after the gauge is removed from the tire valve stem.
U.S. Pat. No. 4,793,177, issued Dec. 27, 1988 to the present inventors describes a combination tire valve and pressure gauge which utilizes an air pressure sensitive bellows. Movements of the bellows are mechanically translated to a rotating air pressure indicator by means of a push rod. A mating pair of gears, one of which is disposed on the push rod, and the other of which is disposed within the indicator, serve to convert the linear movement of the push rod into rotational movement of the indicator. The present invention includes a simpler, more efficient device.
The practical incorporation of an air pressure gauge within a tire valve stem has long been attempted. Prior art patents such as U.S. Pat. No. 2,190,530, Tire Gauge, issued Feb. 13, 1940 to W. S. Clarkson; U.S. Pat. No. 1,400,848, Pressure Gage, issued Dec. 20, 1921 to T. W. Anderson; U.S. Pat. No. 1,606,740, Tire Stem Pressure Gauge, issued Nov. 16, 1926 to A. Badowski; and U.S. Pat. No. 3,246,679, Combination Valve and Pressure Gauge, issued April 19, 1966 to E. J. Stealy, exemplify significant prior art.
Clarkson teaches a tire gauge that is designed for mounting upon a tire valve stem in which the tire valve core has been removed. The device includes a cylindrical housing having a bellows and an opposing spring disposed therewithin. A rotary dial is mounted upon a shaft having a spiral groove on its external surface. A pin whose vertical movement is actuated by the bellows is slidably mounted in the spiral groove, such that vertical movement of the bellows and pin will cause rotation of the dial through the interaction of the pin in the spiral groove.
Anderson teaches a pressure gauge incorporation within a valve stem (see FIG. 2), having an elastic diaphragm G which, per column 1, line 52, may include other pressure responsive means. The diaphragm is restrained by a calibrated spring K, and a rod L extends through a hole in a support head W to terminate in a rack N. The rack N meshes with a pinion O residing on a shaft P which also holds a beveled gear Q which meshes with a beveled gear R disposed on a rotatable shaft S. The rotatable shaft S contains a rotary pressure indicator M having numerals disposed thereon which are viewed through a window T. An air channel C is disposed in the wall of the tire stem to transmit air from the check valve B to the tire. It is therefore to be appreciated that Anderson teaches a relevant but complicated mechanism.
Badowski, U.S. Pat. No. 1,606,740, teaches a tire stem pressure gauge device which includes a bellows-type extensible member 17 which expands in its length within the tire stem depending upon the tire pressure. The bellows 17 is apparently engaged to a vertically-extending pressure indicator 14 which displays tire pressure as a direct function of the extension of the bellows-type member 17. The Badowski device is designed to accommodate tire stems differing in design from those currently available, and it is not readily apparent how this design could be accommodated within tire stems currently available.
Stealy, U.S. Pat. No. 3,246,679, teaches a combination valve and pressure gauge which is incorporated within the conically-shaped tire valve stem designs currently utilized. In Stealy, a pressure-sensitive elastic chamber 62 communicates through bore 60 with the inner tire air pressure. The chamber 62 expands against a calibrated spring 64 and a rod 54 projects through the upward portions of the tire stem and terminates in an indicator 55. Thus, the longitudinal extension of the elastic chamber 62 is directly reflected in the longitudinal extension of the indicator 55. Tire pressure markings are disposed upon a clear tire valve cap 15 to correlate with the outward extension of the indicator 55. Thus, a drawback to the Stealy device is that the tire cap 15 must be fully screwed onto the tire valve nozzle in order to determine the pressure within the tire. A user, upon inflating the tire, might have to screw the cap onto the nozzle several times to achieve the desired pressure.
Other patents of interest are U.S. Pat. No. 1,411,917, Tire Alarm and Gauge, issued April 4, 1922 to W. A. Harris; U.S. Pat. No. 1,136,901, Safety Valve Mechanism For Pneumatic Tires, issued April 20, 1915 to W. M. Myers; U.S. Pat. No. 1,268,467, Pressure Connection and Gage, issued to C. I. Jacobson and A. L. Fowler, June 4, 1918; U.S. Pat. No. 4,058,009, Arrangement for Monitoring Pneumatic Tire Inflation Pressure, issued to Etter-Felix on Nov. 15, 1977; U.S. Pat. No. 4,244,214, Visual Tire Valve, issued to William F. Curran on Jan. 13, 1981. Harris, U.S. Pat. No. 4,411,917, teaches a tire gauge wherein the pressure indicator is actuated through a series of gears; it appears to be more relevant to applicant's prior invention U.S. Pat. No. 4,793,177, described hereinabove than to the present invention. Myers, U.S. Pat. No. 1,136,901, teaches a rather complicated tire valve attachment mechanism in which the indicator is apparently actuated by a gearing arrangement that rides on a sliding, piston type device; it appears to be more relevant to applicant's prior invention, U.S. Pat. No. 4,793,177, described hereinabove. Jacobson, U.S. Pat. No. 1,268,467, depicts a complicated device that is not readily understandable but appears to be less relevant than Anderson, Badowski or Stealy. Etter-Felix, U.S. Pat. No. 4,058,009, teaches a device which is not readily substitutable for a tire valve stem, and does not appear to be as pertinent as Anderson, Badowski or Stealy. Curran, U.S. Pat. No. 4,244,214, teaches a tire valve for mounting over a valve stem and is therefore not a device designed to be incorporated within a valve stem. Curran includes a window which depicts one of three colored bands to indicate over-inflation, proper inflation and under-inflation. A calibrated spring which resists movement of an air flow control rod is utilized to control which color is shown in the window.